When a joint is injured either by trauma or by surgery scar tissue can form which prevents full range of motion of that joint. Obviously, this is a disadvantageous condition and should be corrected if possible. Often, such correction involves an attempt by the injured or those assisting the injured to gradually (often over a period of months) manipulate the joint so that full range of motion is eventually achieved.
Full range of motion of a joint depends upon the anatomy of that joint and on the particular genetics of each individual. Typically, joints move in two directions, flexion and extension. Typically, flexion is to ‘bend the joint and extension is to straighten the joint; however, in the orthopedic convention some joints only flex. For example, the ankle has dorsiflexion and plantarflexion. Other joints not only flex and extend, they rotate. For example, the elbow joint has supination and pronation, which is rotation of the hand about the longitudinal axis of the forearm placing the palm up or the palm down.
There is a need for a class of orthotics which promote an increase in range of motion of the joint rather than to merely provide support. One such series of devices is called the Joint Active System, Inc. It combines a traditional orthotic with limb cuffs on each limb segment and a special hinge joint connecting the two cuffs. This special hinge joint has a ratchet system which allows the hinge to be sequentially bent or straightened with a special wrench or knob. If the cuffs are attached to each limb segment and the hinge is slowly bent then the joint is typically forced into flexion. Similarly, if the hinge is slowly straightened after being strapped on a bent joint, the joint is also straightened. This system relies upon the patient to strap a cuff on to each limb segment. This is difficult to do particularly if the joint to be treated is the arm needed to strap the brace. Furthermore, the pressure on each limb segment by each cuff is very painful as the joint is bent or straightened. Lastly, the ratchet system does not allow for instant release of the pressure used to force an increase in the range of motion.
Another series of devices is made by Dynasplint Inc. These devices are similar to the Joint Active System in that there is a cuff for each limb segment and a special hinge designed to promote an increase in range of motion. With the Dynasplint system, the hinge contains a special set of springs that, when tightened, will put a low load of pressure on the cuffs to bend or straighten. The same objections apply to the Dynasplint as they do to the Joint Active System. The cuffs are uncomfortable, the device is hard to put on and there is no instant release of the pressure. With this system the device must be worn for hours at a time to be effective.
There are other devices available which use inflatable bladders around a joint. They tend to use the bladder(s) to provide support across the joint. Such inflatable bladders are positioned across the joint or in near proximity to the joint.
Such conventional orthosis devices may be designed for support across a joint. In general an orthosis connects one limb segment to another across a joint. The connection is either a rigid member or a hinged joint. In this way orthotics work to support the joint as a means of protecting it. General reference is made to U.S. Pat. Nos. 5,542,911, 5,378,224, 5,348,530, and 5,730,710.
One particular device which uses the bladder(s) to provide support across the joint is also shown in U.S. Pat. No. 5,514,081 to Mann, which uses the inflatable bladder to cross the elbow joint to provide support for an elbow with a flexion contracture (the elbow joint can not fully extend). This device places the inflatable bladder across the joint so that when it inflates it holds the elbow in full extension. This device does not appear to include rigid structural members. Further, it does not isolate the bladder distant to the joint, thus maximizing the biomechanical forces across the joint for promoting elbow extension.
U.S. Pat. No. 3,581,740 has an air bladder which crosses multiple finger joints of a hand as well as the wrist. Upon inflation, the hand is moved to a normally extended, spaced apart, condition.
Some prior art patents use inflatable members to gain range of motion in the hand. U.S. Pat. No. 4,671,258 uses a cyclical therapeutic joint exerciser by inflating a pouch that crosses the joint and a spring steel insert that automatically bends the joint when the inflatable pouch is not inflated. U.S. Pat. No. 4,807,606 uses bladders around the joints in the 3 hands to exercise the joints. That is to say, the bladders are inflated and deflated sequentially with a pump device to flex and extend hand joints.
U.S. Pat. No. 5,056,504 uses the inflatable bladder in the palm against a rigid structure to push the fingers into extension. However, this U.S. Pat. No. 5,056,504 patent includes a bladder which “crosses the joint”, which is not only potentially painful to the user if the joint has undergone surgery, but is not optimally biomechanically efficient in the distribution of forces as will be described later with respect to applicant's invention.
Therefore, it may be seen that there is a need in the art to provide an improved orthotic device, which can be used to straighten (“orthoun” means to straighten) limbs or joints. Therefore, it may be seen that there is a need in the art for an orthotic device and method of using same which provides optimal biomechanical distribution of load.